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By I M. Platten, Y Xie

Narrow vein gold mineralisation generally contains both fine (<100 ¦m) and coarse (>100 ¦m) gold particles. The in situ size and shape, deportment, distribution and abundance of the particles controls deposit sampling characteristics, grade distribution and metallurgical properties. Particles can range from individual disseminated grains, clusters of particles and masses above 1 cm in size. At each end of the coarse-gold to fine-gold spectrum, the samplability of a deposit ranges from relatively simple for fine-grained disseminated gold particles, through to extremely difficult for very coarse particles. Deposits generally show a background grade of mineralisation dominated by disseminated fine gold particles. Drilling will resolve the background grade well, though is likely to considerably understate the grade related to the coarser gold particles. Gold mineralogy has a significant impact on metallurgy, with key factors affecting recovery being particle size, deportment, liberation parameters and silver content of gold minerals. For coarse gold particles the focus should be on liberation and the early removal of the particles from the mill circuit by gravity concentrators and gold traps. Finer particles will require more grinding to liberate prior to flotation or cyanide extraction. The determination of gold particle sizing is thus required to minimise evaluation and geometallurgical uncertainty and lower project risk.

Jan 1, 2008

By Ya Vladimirov D, Yu Khudin M, Kiebanov A. F

Problems of the creation of an automated cartographic system for environmental condition estimation and forecasting in mining region are discussed in this paper. The Geographic Information System (GIS) ARC/INFO is offered as the platform for such a system. A breadboard model of the system was tested on the example of Kemerovo province (Kuznetsk coal basin), the most ecologically impacted mining region of Russia. As a result parameters of territorial distribution of integrated adverse environmental impact of the industrial enterprises are reviewed. Administrative regions of Kemerovo province were rated according to a degree of environmental pollution. Further, specific weight of various industries in pollution of region is determined.

Jan 1, 1995

The Directional Drill Monitor (DDM) is an advanced instrument for real time in hole surveying. It was developed by Du Pont (Australia) to suit Australian gassy coal mining conditions. The instrument consists of three units: i. Down hole transmitter ii. Acoustic transducer iii. Data receiver processor unit (i.e. up hole unit). This paper describes the function of each unit in detail and highlights the importance of the DDM in long hole drilling efficiency. Surveying is carried out independent of hole depth. Each survey takes 2-3 minutes to complete, the frequency of surveying to control borehole trajectory is determined by the accuracy required for a particular hole.

Jan 1, 1992

That gold will dissolve in sodium hyposlphite solutions is known from the lixiviation of silver and gold ores.The gold will dissolve only in small quantities. According to Stetefeldt, if gold leaf is treated for a time with sodium hyposlllphite solutions of varying strengths solution takes place in every instance, the deviation in quantity being very slight.In order to form hyposulphite double-salts, the gold must become oxidised, the oxygen being derived from the air absorbed by the solution. Consequently, it is the quantity of free oxygen in the solution by, which the reaction is determined, as for one equivalent of gold dissolved one equivalent of caustic soda is set free.

Jan 1, 1901

By Massy-Greene RB

Limited recourse financing techniques reduce the financial exposure of equity holders to major mining projects by transfering some of the risks to the banks which provide loan funds for project development. This can only be achieved by a clear understanding of the principles involved. Engineering and management decisions on how the resource is to be developed and extracted must be made in the light of lender's requirements. The structure of sales contracts, joint venture agreements and many other documents can be important in limited recourse financing. If projections show that the debt can be repaid from project cash flow, loan agreements and other arrangements can restrict lenders ability to look to the equity holders for repayment of project loans.

Jan 1, 1981

Key blocks occur on the surface of excavations and on the walls of the ornamental stones and limestone quarries due to the formation of joint planes, fissures, microfaults and quarrying operations. Movements of these key blocks have produced numerous important failures and are responsible for routine overbreak and rock falls accounting for great costs. The thrust of this work is to demonstrate how to delimit zones of poten- tial key blocks (danger zones) in the wall of Bani-Khalid quarry of lime- stone by using the block theory technique (stereographic projection). The final result of this study indicated that, there are three potential key blocks, the most critical one has been determined. To treat the problem, we sug- gest either to provide timely support to prevent the movement of this block, or to analyze it further in hopes that available friction on the faces will hold it safely in place.

Jan 1, 1989

By M Magee, D Way

The Mount Isa Copper Concentrator was commissioned in 1973. In 1991, two autogenous grinding mills were installed replacing two stages of crushing, one stage of rod milling and one stage of primary ball milling. The cyclone overflow P80 of the secondary ball milling circuit was reduced to 120 microns due to the increased operating power in the AG/SAG mill circuits. A study of the mineralogy of the milled products and the plant flotation recovery indicated that the installed secondary grinding energy was more than what was required for adequate liberation of the chalcopyrite and half of it had potential for more effective use elsewhere. Halving the secondary grinding energy meant only one of the two secondary ball mills would be needed. The predicted saving in operating cost of one less ball mill was more than two million dollars per annum. This paper summarises various plant trials that were conducted in the Copper Concentrator to decommission one of the two secondary ball mills.

Jan 1, 2004

By R Grogan

The Ungay-Malabago polymetallic deposit, currently owned by Lafayette Mining, is located on the eastern end of the island of Rapu-Rapu which lies east of the city of Legazpi in the Philippines. The island is sparsely populated and has largely been deforested by extensive logging some 30-40 years ago.The deposit is situated on a plateau some 200 m asl and lies about one kilometre inland from the coast. The site topography is difficult with minimal flat areas for plant facilities. The region around Legazpi is subject to volcanic activity and though the island is not affected it is in a seismic zone. There is no other mining or other industrial activity on the island, the local inhabitants being engaged in subsistence farming and fishing. These activities place a high level of responsibility on the mine operator with regard to the environment and the provision of employment and training to the local inhabitants. Although no previous mining was carried out at Ungay, shallow pit mining for high-grade direct smeltable copper ore has occurred during the mid-1900s in an area, known as Hixbar, some 2 km west of the deposit This area is currently being explored by Lafayette.

Jan 1, 2002

By King D

Recent field experiments in the United Kingdom (Buchanan, 1979) have shown that the in-seam technique is capable of detecting a 1m fault in a 3m seam, at a range of 280m and with a resolution of ¦40m. Comparable tests in Australian collieries are proceeding. Although the practicality of an implementation of the technique on a routine basis remains to be demonstrated, the potential of the technique for the prediction of outbursts clearly warrants detailed examination. This potential will,depend, inter alia, on the level and scale of variations in elastic (and anelastic) properties of bodies of coal undergoing stresses associated with mining. Available data, mainly from studies of the seismic properties of gas saturated reservoir rocks, confirm the intuitive view that stress increases give rise to increases in seismic wave velocity and decreases in wave attenuation, markedly at low stresses (as pore spaces close with little resistance) but less so as stress increases. Such increases are of the same order as aniso- tropic effects, but should provide impedance contrast sufficient for detection by in-seam seismic methods. At higher stresses, cracks form within the rock mass. Results from research on earthquake prediction provide some clues to the behaviour of sedimentary rocks sub- jected to large stresses. In particular, the

Jan 1, 1980

By C Nucifora, M Landers, J Jones, G Maddocks, K Mandaran, A Forbes, W Wilson, S Newman

Glencore’s Mount Isa Mines Limited (MIM) operates the Mount Isa open cut and underground copper (Cu) and zinc-lead (Zn/Pb) mines near Mount Isa in Queensland, Australia. Tailings from processed Cu and Zn-Pb ore is contained in a 1,315 ha shallow (< 35 m deep) multi-cell valley fill tailings storage facility (TSF). Static geochemical testing conducted by MIM over the life of mine (LoM) verifies that the Cu, and Zn-Pb tailings has a wide range in sulfide content and diverse mineralogy with significant acid neutralising capacity (ANC) in some samples. The tailings are predominantly classified as potentially acid forming (PAF) using static analytical methods. Kinetic leach testing using free draining columns and humidity cell tests simulating tailings placed on the surface of the TSF suggest that the tailings samples are likely to remain non-acid forming (NAF) for 10 to 40 years under aerial exposure, and much longer than this under saturated conditions within the TSF. During this period of weathering, as ANC is depleted, the neutral pH drainage may contain elevated concentrations of some elements including sulfate, manganese and zinc. Only when the ANC is depleted would the tailings then begin to produce acid drainage. CITATION:Mandaran, K, Jones, J, Nucifora, C, Maddocks, G, Landers, M, Forbes, A, Wilson, W and Newman, S, 2018. Mount Isa Mines Rehabilitation Materials Sampling and Analysis program for closure planning, in Proceedings Life-of-Mine 2018, pp 138–140 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Crellin D, Reed SM

The paper presents details of borehole instrumentation schemes for the purposes of monitoring rock and fill deformations associated with groundwater in underground and surface coal mines. The instruments are described which measure rock mass displacements, permeability changes and alterations to hydrology. Methods of installation are detailed and the applicability of instruments discussed. Reduction and interpretation of results are detailed.

Jan 1, 1988

Contractors are used extensively in the development of underground mines in Australia. Often problems arise, some originating as far back as the feasibility stage of projects, through inexperience, lack of preparation and inflexibility by both parties.Guidelines are put forward for both principals and contractors which are seen as necessary to ensure that disputation is avoided and the full benefits of the use of contractors are obtained.

Jan 1, 1985

THIS instrument, depends on the principle that, over a short period, the surfaee of a porous substance from which a liquid is evaporating receives the same amount of heat by conduction, convection, and radiation as it loses in the latent heat of the evaporating liquid. If, then, the amount of heat being received by a surface can be measured, the rate of evaporation can also be obtained. The Kata thermometer is also based on this principle differently applied.The instrument, as shown in Fig. 1, consists essentially of a thermometer with a sliding which is divided by three pointers into two equal parts which may be spaced so as to cover a distance of, for example, 5° of the thermometer scale. The instrument is calibrated so that the amount of heat required per unit area of the bulb to raise the menissus is known. The method of using the instrument is as follows:The slide is first set so that thc central pointer is at the temperature of the evaporating surface.The thermometer is cooled by any convenient means so that the meniscus is several below the lowest pointer. The thermometer is then placed near the evaporating surface, when the Ineniscus begins to rise and the time taken for it to rise from the lowest to the top pointer is measured. From this and the calibration results the amount of heat retained per unit area of the bulb at the mean temperature...

Jan 1, 1928

By J Koppe, J F. Costa

A fundamental error of sampling occurs when a sample is extracted from a larger mass of ore or lot. The act of sampling requires that all particles belonging to the lot have an equal chance of being extracted. This type of sampling is called unbiased sampling. The sampling equipment (herein referred to as the sampler) should be constructed with some additional mechanical characteristics to guarantee that the samples will be unbiased. Samplers, extracting increments from a continuous flow, such as a conveyor belt, collect aliquots at regular time intervals. These time intervals relate to the number of aliquots extracted from a given mass of lot, whilst passing through the continuous flow. The frequency of extractions will influence the precision or the error of the sample (integration error). Further, the ore variability influences the amount collected from the continuous flow. Normally, the sampling protocol utilised is designed for the extractions obtained from the conveyor belt, omitting any error committed during this operation, ie the error of extracting from the continuous flow. This study aims to analyse the error of sampling a continuous flow by using a variogram with added on auxiliary functions. Each different piece of material passing through the flow will exhibit a distinct temporal variogram, which should influence the frequency of the samples being extracted for each chosen sampling error. The methodology used is presented in the form of a case study from a coal processing plant.

Jan 1, 2005

Iron from the blast furnace constitutes the starting point in steel production and any increase that can be made in iron production will bring about important repercussions in a long line of processes. Coke constitutes a major item in furnace operation and consumption at the Port Kembla Works of Australian Iron & Steel Ltd. has been approximately 1,850 lb. per ton of iron produced on ore practice, or 3,000 tons per day.For many years coke quality has been subject to much criticism by furnace operators throughout the world, sometimes with little real grounds. Whatever the merits of previous arguments, and they were no doubt two-sided, the development of bigger furnaces has focused attention on coke strength. At the same time a decrease in the quantity of good quality coking coals available to many plants has stimulated research in this field.Extensive coke research has been carried out overseas, and in Australia the.B.H.P. Organization is now actively doing likewise in its Central Research Laboratories at Shortland near Newcastle, N.S.W., and works research groups at Newcastle and Port Kembla Steelworks. Similar work has been initiated in the beehive coking industry. Such work is in its infancy and this paper will outline the direction of the activities at Port Kembla rather than propound specific solutions.At Port Kembla good quality coking coals are readily available from the IIIawarra coalfield. The seams generally mined for coking are Bulli and Wongawilli and to a much smaller extent Tongarra. Characteristics of these coals appear in Table 1.

Jan 1, 1958

The Australian Mineral Industry has to compete on world markets, so its mineral research has to be aware of overseas developments, it must be of world class, and it must utilise as many ideas as possible in order to solve those problems that uniquely affect Australian minerals processing. North American mineral and resource research may be taken as a guide to world government, industrial, contract, and entrepreneurial research trends and ideas. A number of interesting findings are noted that may guide Australian developments and strategies for the future, in minerals research and exploitation.

Jan 1, 1986

By J Williams

The recent drought has highlighted the finite nature of AustraliaÆs divertible water resources. According to AustraliaÆs recently completed National Land and Water Resources Audit, development of water resources in southern Australia has reached or exceeded sustainable extraction limits. Similarly, 161 out of 538 groundwater management units are either totally allocated or already over allocated. Whilst mining only uses about three per cent of diverted water resources, water scarcity may be a major factor that determines whether potential mines can be developed in the future. Furthermore, the development of extraction and processing facilities that limit water use and maximise the re-use the waste water streams will be even more fundamental features of the mining industry in the 21st century than they are at present. There are encouraging examples where innovative water re-use technologies are significantly reducing the water used per unit of mined product. Whilst mining in the areas of Australia draining to the tropical seas may be less constrained by a current lack of water (60 per cent of divertible water resources drain into the Timor Sea, Gulf of Carpentaria and north east Coral Sea), it is highly probable that there will be increasing demand for these waters from the irrigation industry, whilst pressure will also be applied to ensure that environmental flows that benefit the coastal fishing and prawn industries are maintained. In the Great Artesian Basin, current research is demonstrating that the groundwaters are being recharged at rates considerably lower than current extraction. Whilst some other groundwater basins in arid and semi-arid Australia have currently untapped resources, these water are often relatively saline and/or may be intimately linked with key ecosystems in discharge areas. This paper presents an overview of the current state of our water resources and examines some of the key water use issues including allocation, use and reuse, environmental flows and competing demands on the resource that will ensure that water issues remain high on the policy agenda for mining, irrigation and other water users.

Jan 1, 2003

In a state-of-the-an review of predictive methods for longwall support load calculation, special respect is paid to those techniques which enable actual roof conditions and local lithology of strata to be involved. Principal systems of roof examination include the borehole perforation test and seismic velocity measurements. Roof strata stability is related to caveability classifications and roof inclination due to subsidence. The critical analysis of both load resistance prediction methods and roof stability classifications shows that each has its own value of reliability level. The present research opportunities analysed underline the significance of developing fully reliable prediction techniques as needed by the coal industry.

Jan 1, 1991

By M Noy, P Hawkes

Improvements in the drill and blast process can impact on loader performance in a number of ways. The main effects being improved loading cycle times, less non-productive cycles such as oversize removal, clean-up and face raking and better bucket fill factors. The impact of improved loading cycle times on the overall cost and productivity of the load and haul cycle is very much dependent on the loader truck match and the management of the haul fleet. Previous work has shown that a 20 per cent improvement in dig cycle times may only lead to three per cent or less improvement in the overall productivity of the load and haul process. However, improving the mass loaded per pass by five per cent will lead to a five per cent improvement in productivity for any given haul fleet situation, assuming sufficient truck capacity. Work by Orica Explosives at Lab ChrysotileÆs Thetford Mine, Quebec, Canada showed a relationship between muckpile fragmentation and truck payload. With this in mind, work was carried out to determine the effect differing muckpile fragmentation distributions can have on excavator bucket fill factors. This work was performed in the laboratory to a 1:100 scale. Nine different distributions were used. These were characterised by the Rosin Rammler parameters, xc the characteristic size, and n, the uniformity index. The values of xc and n used were modelled on those previously measured at a Sydney quarry. For the range of distributions measured, it was found that the fill factors were lowest at a low characteristic size and a high uniformity index and highest at a high characteristic size and a low uniformity index. In other words the best fill factors were achieved with a more dispersed muckpile distribution with a larger characteristic size. The difference in fill factors was 16 per cent indicating that controlling the drill and blast process to produce a specific muckpile distribution can have a significant impact on the overall cost-efficiency and productivity of the load and haul process. Field measurement by Orica Explosives at a quarry in Canada supports this conclusion showing improvements of up to seven per cent in average bucket load by either increasing the characteristic size or decreasing the uniformity index of the muckpile.

Jan 1, 1999

Several years and millions of dollars later, the mining and extractive industries have now started to receive and implement industry based standards aimed at achieving better performance and output from the employee. IFAP in conjunction with the mining and quarrying industry has developed a range of training courses aimed at achieving the benefits that can be gleaned from application of these standards. The establishment of a career path and appropriate training packages for personnel involved in the handling and use of explosives provides industry with a training system that previously did not exist. The opportunity to receive quality training based on industry standards and aimed at achieving industry goals will now enable the industry to optimise itÆs explosives applications.

Jan 1, 1999